Which hormone is primarily responsible for milk production in breastfeeding mothers?

Prolactin is the hormone that plays a key role in milk production for breastfeeding mothers. It is secreted by the anterior pituitary gland and its primary function is to stimulate the mammary glands to produce milk in response to the suckling of an infant. When a baby latches on to the breast, nerve impulses are sent to the hypothalamus, which then encourages the anterior pituitary to release prolactin. Higher levels of prolactin result in greater milk synthesis, making it essential for breastfeeding success.

While estrogen and progesterone contribute to the development of the mammary glands during pregnancy, they do not directly influence milk production post-delivery like prolactin. Oxytocin is another important hormone, as it is responsible for milk ejection or let-down during breastfeeding; however, it does not initiate milk production itself. Understanding the specific roles of these hormones highlights why prolactin is identified as the primary hormone responsible for initiating and maintaining milk production.